The Suffolk County Water Authority has launched an initiative to urge East End homeowners, particularly those in Southampton, East Hampton and Southold, to curb their water usage and reduce the strain on the underground aquifer system.

According to the authority, residents and businesses on the East End consume more water in summer than customers in any other service area, especially from midnight to 6 a.m.

Suffolk residents, including those on the East End, use about 160,000 gallons annually, well below the millions consumed by the authority’s top users.

Billionaire industrialist David Koch, 76, who has a 4-acre estate in Southampton, again headed the water authority’s list of top 10 residential and commercial water users between July 2015 and June 30 of this year, consuming 22,572,022 gallons. Koch, who co-owns Kansas-based Koch Industries with his brother, Charles, has been the county’s heaviest water user for five years.

“Mr. Koch’s Suffolk County home serves as a year-round residence and utilizes an energy-efficient and geothermal heating and cooling system,” a spokeswoman wrote in an email Tuesday. “This environmentally-friendly system relies on the earth’s stable temperature to heat and cool his family’s home. Though increased water usage is required, the system is more energy-efficient than oil or gas systems that are used in most residences.”

The top residential and commercial water users include consumers in Bridgehampton, Southampton, Water Mill, Amagansett and East Hampton.

The No. 2 user is a private home registered to Meadowlark Highland Inc. The Bridgehampton-based business used 13,489,656 gallons of water in the past year. Ickenham Limited, a foreign corporation in the Bahama Islands, ranked third with a home on Meadow Lane. The residence, which was sold to the corporation in 2011 for $32.5 million, used 11,022,902 gallons. Neither company responded to requests for comment.

In June, the water authority sent out a mailing to 38,000 East End customers about its new East End Water Wise Club program. The agency also contacted the top 300 water users on the East End. Roughly 30 percent of the top users on the North Fork responded with a verbal commitment to try and implement some of the program’s suggested measures, such as adjusting lawn irrigation times and purchasing water-saving products. Agency officials said they are still gathering data from the South Fork.

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The voluntary program offers conservation tools and tips and encourages residents to sign up and receive account credits on their water bills for purchasing water-efficient equipment — such as rain sensors, low-flow showerheads and faucet aerators — from the Environmental Protection Agency’s “WaterSense” program, water authority officials said.

“We are hoping that customers will take part and be stewards of the aquifer,” said Tyrand Fuller, director of strategic initiatives for the water authority, which serves about 382,000 customers.

Legislators and water authority staff met last week with residents in Southampton to discuss the program.

Catherine Danner, 60, who has lived in Sag Harbor for 13 years, lamented the high usage rates.

“I have been in parts of the world where water is a precious resource,” she said. “There should be smarter ways of using water here.”

Fuller said the water authority will consider mandatory measures to enforce water conservation if not enough residents sign up for the Water Wise program.

Southold Town Supervisor Scott Russell said he will meet with water authority officials to discuss the initiative.

Southampton Town Supervisor Jay Schneiderman said he had not heard from water officials about the program.

Larry Cantwell, East Hampton’s town supervisor, said he needs to learn more about the program, but added, “We should all be able to do what we can to conserve water, especially groundwater.”